JP2005322961A - Communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication terminal capable of preventing deterioration in reception state when the reception power of a broadcast wave is small by using a broadcast reception means to hardly receive the effect of a disturbing wave from a wireless communication means even when the wireless communication means and the broadcast reception means are mounted in one and the same housing. <P>SOLUTION: A wireless communication section 2 receives a mode switching signal 16 from a mode switching circuit 15, reaches the state of a communication stop wherein no communication can be established when the mode switching signal 16 is at a low level, or reaches the state of a communication non-stop wherein communication can be established when the mode switching signal 16 is at a high level. An automatic gain control circuit 13 adjusts amplitudes of AGC signals 17, 18 so that an input level to an A-D conversion circuit 11 is a proper level as first control. Further, the automatic gain control circuit 13 sets maximum values of the AGC signals 17, 18 to a prescribed maximum setting value when the mode switching signal 16 is at a high level as second control. The second control is carried out in preference to the first control. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication terminal apparatus including a wireless communication unit and a broadcast receiving unit, and more particularly to a mobile phone incorporating a terrestrial digital television.

  In recent years, mobile phones have become widespread with the addition of not only conventional call functions but also e-mail functions and Internet browsing functions. On the other hand, terrestrial digital television broadcasting has been started in 2003 as a new broadcasting that replaces the terrestrial analog broadcasting currently being viewed in Japan.

  This terrestrial digital television broadcasting technical standard ISDB-T (Integrated Services Digital Broadcasting) employs OFDM (Orthogonal Frequency Division Multiplexing), which uses a large number of carriers as a modulation method, and a plurality of propagation paths (such as reflection by a building). It is also possible to suppress ghost interference due to (multipath). In addition, ISDB-T defines a plurality of transmission modes that define carrier intervals, modulation schemes for each carrier, and guard intervals in the time axis direction that are provided for each effective symbol length. Is allowed. Actually, an optimum format is selected from these according to services such as fixed reception and mobile reception. In ISDB-T, one channel (bandwidth of about 5.6 MHz) is divided into 13 segments (1 segment = about 430 KHz), and the modulation method is changed in units of this. Thus, the broadcasting station can arbitrarily determine the signal configuration such as audio broadcasting and high-vision broadcasting, standard fixed broadcasting and mobile broadcasting on one channel. Furthermore, ISDB-T incorporates interleaves in the time axis direction, and since radio waves to be used are suitable for transmission to mobile objects, mobile receivers such as in-vehicle TVs, PDAs (Personal Digital Assistants) and mobile phones. One of the major features is that stable reception is possible even with a portable terminal such as a telephone.

  In view of the above, in recent years, a communication / broadcast integrated service that combines a mobile phone and a terrestrial digital TV broadcast is expected. Specifically, a service has been proposed in which a terrestrial digital television broadcast can be viewed on a mobile phone with a built-in terrestrial digital television, and information related to the television broadcast can be acquired via communication.

  On the other hand, a broadcast receiver of a conventional receiver such as a terrestrial digital television broadcast receiver has a configuration as shown in FIG. The broadcast receiving unit includes a first filter 28 connected to the antenna 27, a first variable gain amplifier circuit 29, a frequency conversion circuit 30, a second filter 31, a second variable gain amplifier circuit 32, and an A / D conversion. A circuit 33, a demodulation circuit 34, an automatic gain control circuit 35, and a saturation detection circuit 36 are provided.

  A necessary frequency component is extracted from the frequency components received by the antenna 27 by the first filter 28, amplified or attenuated by the first variable gain circuit 29, and converted to a desired frequency band by the frequency conversion circuit 30. The Thereafter, further necessary frequency components are extracted by the second filter 31, amplified by the second variable gain circuit 32, analog-digital converted by the A / D conversion circuit 33, and demodulated by the demodulation circuit 34.

  The automatic gain control circuit 35 receives the A / D conversion data 37 that is the output of the A / D conversion circuit 33 and the saturation detection signal 38 from the saturation detection circuit 36, and receives the AGC to the first variable gain amplification circuit 29. The signal 39 and the AGC signal 40 to the second variable gain amplifier circuit 32 are output. When the AGC signal 39 increases, the gain of the first variable gain amplifier circuit 29 increases. When the AGC signal 40 increases, the gain of the second variable gain amplifier circuit 32 increases.

  Here, as the first control, the automatic gain control circuit 35 adjusts the magnitudes of the AGC signal 39 and the AGC signal 40 so that the input level to the A / D conversion circuit 33 becomes an appropriate level. Further, as the second control, the automatic gain control circuit 35 controls the AGC signals 39 and 40 to be small when the saturation detection signal 38 indicates saturation. The second control is performed with priority over the first control. That is, when the AGC signals 39 and 40 are controlled to be reduced by the second control, the AGC signals 39 and 40 cannot be increased by the first control (for example, Patent Document 1). reference).

  FIG. 6 shows a main configuration of the automatic gain control circuit 35. The automatic gain control circuit 35 includes an averaging circuit 41, an arithmetic circuit 42, a first D / A conversion circuit 43, and a second D / A conversion circuit 44.

  The averaging circuit 41 calculates the average power value of the A / D conversion data 37. Corresponding to the first control, the arithmetic circuit 42 compares the average power value from the averaging circuit 41 with a reference value, and if the average power value is large, a digital value such that the AGC signals 39 and 40 become small is obtained. The first D / A converter circuit 43 outputs a digital value that is output to the first D / A converter circuit 43 and the second D / A converter circuit 44 so that the AGC signals 39 and 40 increase if the average power value is small. 43 and the second D / A conversion circuit 44 (see, for example, Patent Document 2). However, in response to the second control, when the saturation detection signal 38 indicates saturation, the arithmetic circuit 42 converts a digital value such that the AGC signals 39 and 40 are reduced to the first D / A conversion. The signal is output to the circuit 43 and the second D / A conversion circuit 44. The first D / A conversion circuit 43 and the second D / A conversion circuit 44 convert the digital value from the arithmetic circuit 42 into an analog value, and generate AGC signals 39 and 40.

  The saturation detection signal 38, which is the output of the saturation detection circuit 36, corresponds to the output in which the output of the frequency conversion circuit 30 to which the saturation detection circuit 36 is connected saturates the subsequent filter 31 and the second variable gain amplification circuit 32. Is set to represent saturation when approaching within a predetermined value.

As described above, when saturation is detected by the saturation detection circuit 36, the AGC signals 39 and 40 generated by the automatic gain control circuit 35 are reduced, so that the subsequent filter 31 and the second variable gain amplification circuit 32 are reduced. Can be prevented from being saturated.
Japanese Utility Model Publication No. 3-46881 (publication date April 30, 1991 abstract, Fig. 1) JP 2002-77101 A (publication date March 15, 2002, paragraphs 0031 to 0035, FIG. 1)

  When the wireless communication means and the broadcast receiving means are provided in the same housing, the transmission wave from the wireless communication means becomes a very large interference wave for the broadcast receiving means. For example, when the received power of the desired wave received by the broadcast receiving means is about -70 dBm, it is conceivable that the transmission power of the disturbing wave transmitted by the wireless communication means is as large as about 30 dBm, and the frequency characteristics of the antenna of the broadcast receiving means Even if the interference wave is attenuated to some extent by the frequency characteristics of the filter, the reception power of the interference wave input to the broadcast receiving means is still large. In addition, transmission in the wireless communication means is often performed intermittently, and therefore, the change in the received power of the interference wave from the wireless communication means is fast. Here, the interference wave from the wireless communication means includes a transmission wave when the communication terminal device user intends to perform communication, and the communication terminal device automatically bases on the communication terminal device user without intention. This includes transmission waves that inform the station of its location.

  When the conventional broadcast receiving unit receives such an interference wave whose reception power is very large and changes rapidly, there is a problem that the broadcast receiving unit is saturated because the gain adjustment of the variable gain amplifier circuit is not in time.

  Specifically, when such an interference wave is received, saturation is detected by the saturation detection circuit 36, and the AGC signals 39 and 40 generated by the automatic gain control circuit 35 become small. Since the first D / A conversion circuit 43 and the second D / A conversion circuit 44 are connected, the AGC signals 39 and 40 change slowly. For this reason, the change of the interference wave cannot be followed, and the gain adjustment of the first variable gain amplifier circuit 29 and the second variable gain amplifier circuit 32 is not in time.

  Further, when saturation is detected by the saturation detection circuit 36, even if the AGC signals 39 and 40 generated by the automatic gain control circuit 35 are reduced, the interference wave is large, so that the AGC signals 39 and 40 are reduced. There is a possibility that saturation will continue without enough. If the AGC signals 39 and 40 when the saturation is not detected by the saturation detection circuit 36 are set low so that the amount for reducing the AGC signals 39 and 40 is sufficient, the AGC signals 39 and 40 are constantly lowered, so that the broadcast receiving means The reception sensitivity is steadily lowered, and the reception situation is deteriorated when the reception power of the broadcast wave is small.

  The present invention has been made in view of the above problems, and its purpose is to broadcast the influence of interference waves from wireless communication means even when wireless communication means and broadcast reception means are provided in the same housing. An object of the present invention is to realize a communication terminal apparatus that is difficult for reception means to receive and can prevent deterioration of reception conditions when the reception power of broadcast waves is small.

  In order to solve the above-described problem, a communication terminal apparatus according to the present invention includes a radio communication unit that communicates with a radio base station, and a broadcast reception unit that receives a broadcast from the broadcast base station. Mode switching means for switching between a first mode in which communication of the wireless communication means is stopped and a second mode in which communication of the wireless communication means is not stopped, and the reception gain of the broadcast receiving means in the first mode The upper limit is higher than the upper limit of the reception gain of the broadcast receiving means in the second mode.

  The upper limit of the reception gain of the broadcast receiving means in the second mode may be a value that does not saturate the broadcast receiving means due to interference from the wireless communication means.

  The mode switching in the mode switching means may be performed based on an instruction from a user of the communication terminal device.

  The mode switching in the mode switching means may be performed so that the mode is automatically switched to the second mode by a communication start operation of the user of the communication terminal device.

  Moreover, you may have a mode display means to display that a communication terminal device is in a 1st mode, or a communication terminal device is in a 2nd mode.

  As described above, the communication terminal apparatus according to the present invention has mode switching means for switching between the first mode in which communication of the wireless communication means is stopped and the second mode in which communication of the wireless communication means is not stopped. Since the upper limit of the receiving gain of the broadcast receiving means in the first mode is higher than the upper limit of the receiving gain of the broadcast receiving means in the second mode, if the communication mode is switched to the first mode when communication is not performed, transmission from the wireless communication means The broadcast receiving means is no longer saturated due to interference by waves, and the upper limit of the reception gain of the broadcast receiving means can be increased. Therefore, even when the wireless communication means and the broadcast receiving means are provided in the same housing, it is possible to increase the reception sensitivity of the broadcast receiving means and prevent the reception situation from deteriorating when the reception power of the broadcast wave is small. There is an effect.

  As described above, the communication terminal device according to the present invention performs communication because the upper limit of the reception gain of the broadcast receiving means in the second mode is a value that does not saturate the broadcast receiving means due to interference from the wireless communication means. Sometimes, by switching to the second mode, the upper limit of the reception gain of the broadcast receiving means is lowered to a value that does not saturate the broadcast receiving means due to interference from the wireless communication means, and a large interference wave is input from the wireless communication means It is also possible to avoid saturation of the broadcast receiving means. In addition, since the reception gain is continuously set low while the wireless communication means is performing communication, it is not necessary to adjust the gain in time even if the received power of the interference wave from the wireless communication means changes rapidly. Therefore, even when the wireless communication means and the broadcast receiving means are provided in the same housing, there is an effect that the broadcast receiving means can be hardly affected by the interference wave from the wireless communication means.

  In the communication terminal device according to the present invention, as described above, since the mode switching in the mode switching unit is further performed based on an instruction from the user of the communication terminal device, the mode switching is performed at a timing desired by the user of the communication terminal device. Is done. Therefore, the user of the communication terminal apparatus can arbitrarily select whether to increase the upper limit of the reception gain in a state where communication is stopped, or to lower the upper limit of the reception gain in a state where communication is not stopped. There is an effect.

  In the communication terminal device according to the present invention, as described above, since the mode switching in the mode switching unit is further automatically switched to the second mode by the communication start operation of the user of the communication terminal device. When performing communication, there is no need to perform a switching operation from the first mode to the second mode. Therefore, there is an effect that it is not necessary to increase the complexity of the operation when the user performs communication.

  As described above, the communication terminal device according to the present invention further includes mode display means for displaying that the communication terminal device is in the first mode or that the communication terminal device is in the second mode. The user can easily identify the mode. Therefore, there is an effect that the user can appropriately switch the mode according to the situation.

  An embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 shows an embodiment of the present invention, and is a block diagram showing a main configuration of a communication terminal device.

  Referring to FIG. 1, communication terminal apparatus 1 in the present embodiment includes a radio communication unit (radio communication means) 2 that communicates with a radio base station, and a broadcast reception unit (broadcast unit) that receives a broadcast from the broadcast base station. Receiving means) 3 and a mode switching circuit (mode switching means) 15. An antenna 4 for communication is connected to the wireless communication unit 2, and an antenna 5 for receiving broadcast is connected to the broadcast receiving unit 3. The broadcast receiver 3 includes a first filter 6, a first variable gain amplifier circuit 7, a frequency conversion circuit 8, a second filter 9, a second variable gain amplifier circuit 10, an A / D conversion circuit 11, and a demodulation circuit. 12. An automatic gain control circuit 13 is provided.

  A necessary frequency component is extracted from the frequency components received by the antenna 5 by the first filter 6, amplified or attenuated by the first variable gain amplification circuit 7, and converted to a desired frequency band by the frequency conversion circuit 8. Is done. Thereafter, further necessary frequency components are extracted by the second filter 9, amplified by the second variable gain amplifier circuit 10, analog-to-digital converted by the A / D converter circuit 11, and demodulated by the demodulator circuit 12. .

  The automatic gain control circuit 13 receives the A / D conversion data 14 that is the output of the A / D conversion circuit 11 and the mode switching signal 16 from the mode switching circuit 15 and receives the AGC to the first variable gain amplifier circuit 7. The signal 17 and the AGC signal 18 to the second variable gain amplifier circuit 10 are output. When the AGC signal 17 increases, the gain of the first variable gain amplifier circuit 7 increases. When the AGC signal 18 increases, the gain of the second variable gain amplifier circuit 10 increases.

  The wireless communication unit 2 receives the mode switching signal 16 from the mode switching circuit 15, and when the mode switching signal 16 is at a low potential, the wireless communication unit 2 enters a communication stopped state (first mode) where communication cannot be performed. When 16 is at a high potential, communication is not stopped (second mode) in which communication can be performed.

  Here, as the first control, the automatic gain control circuit 13 sets the AGC signal 17 and the AGC signal 18 so that the input level to the A / D conversion circuit 11 becomes an appropriate level regardless of the state of the mode switching signal 16. Adjust the size of. Further, as the second control, the automatic gain control circuit 13 sets the maximum values of the AGC signals 17 and 18 to a predetermined maximum value setting value when the mode switching signal 16 is at a high potential. The second control is performed with priority over the first control. That is, when the maximum values of the AGC signals 17 and 18 are set by the second control, it is impossible to make the AGC signals 17 and 18 larger than the set maximum value by the first control. Here, the first control is performed during the time when the broadcast receiving unit is receiving the broadcast, and the second control is the mode switching signal 16 during the time when the broadcast receiving unit is receiving the broadcast. Performed when the potential is high.

  FIG. 2 shows a main configuration of the automatic gain control circuit 13. The automatic gain control circuit 13 includes an averaging circuit 19, an arithmetic circuit 20, a first D / A conversion circuit 21, and a second D / A conversion circuit 22. A mode switching signal 16 is input to the arithmetic circuit 20.

  The averaging circuit 19 calculates the average power value of the A / D conversion data 14. Corresponding to the first control, the arithmetic circuit 20 compares the average power value from the averaging circuit 19 with a reference value, and if the average power value is large, a digital value such that the AGC signals 17 and 18 become small is obtained. The first D / A converter circuit 21 outputs a digital value that is output to the first D / A converter circuit 21 and the second D / A converter circuit 22 so that the AGC signals 17 and 18 increase if the average power value is small. 21 and the second D / A conversion circuit 22. However, in response to the second control, when the mode switching signal 16 is at a high potential, the arithmetic circuit 20 sets the predetermined maximum value set value as the maximum value of the AGC signals 17 and 18, and the AGC signals 17 and 18 A digital value that does not exceed this value is output to the first D / A conversion circuit 21 and the second D / A conversion circuit 22. The first D / A conversion circuit 21 and the second D / A conversion circuit 22 convert the digital value from the arithmetic circuit 20 into an analog value, and generate AGC signals 17 and 18.

  The maximum value setting value set as the maximum value of the AGC signals 17 and 18 is set as large as possible within a range in which the broadcast receiving unit 3 is not saturated due to interference from the radio communication unit 2. For example, the largest possible reception gain within a range that does not affect the broadcast receiving unit 3 even if communication is performed by the wireless communication unit 2 is measured in advance for several types of transmission intensities and stored in the arithmetic circuit 20, and the stored data The maximum value setting value is set by reading out the recording data corresponding to the transmission intensity detected by a control unit (not shown) provided in the communication terminal device 1 from the inside. Alternatively, the control unit provided in the communication terminal device 1 is set by calculating an appropriate reception gain based on the detected transmission intensity and outputting the data to be set to the maximum value to the arithmetic circuit 20. The Alternatively, the user of the communication terminal device 1 can set the maximum value setting value according to the reception status. For example, each time a specific switch provided in the communication terminal device 1 is pressed, data selected from data prepared in advance is output as a maximum value setting value.

  If the maximum value setting value is determined based on the average power value from the averaging circuit 19 in the arithmetic circuit 20, the maximum values of the AGC signals 17 and 18 are set according to the received intensity of the desired wave. Can do.

  FIG. 3 is a timing diagram illustrating an example of adjusting the maximum value of the AGC signal. As shown in FIG. 3B, the mode switching signal 16 has a high potential in a communication non-stop state in which communication can be performed, and a low potential in a communication stop state in which communication cannot be performed. Transmission in the wireless communication unit 2 is performed as shown in FIG. 3A during a period in which the mode switching signal 16 is at a high potential. Corresponding to the mode switching signal 16, the maximum value of the AGC signal 17 or 18 is set low while the mode switching signal 16 is at a high potential as shown in FIG.

  The mode switching in the mode switching circuit 15 is performed based on an instruction from the user of the communication terminal device 1. For example, as shown in FIG. 4, the mode change signal 16 is configured such that a high potential and a low potential are alternately switched and held by pressing a mode change switch 24 provided on a mobile phone (communication terminal device) 23. Yes. When the mode switching signal 16 is held at a low potential, when the user of the mobile phone (communication terminal device) 23 performs a communication start operation such as inputting a telephone number or displaying a mail transmission menu, The switch is automatically switched from a low potential to a high potential without pressing the changeover switch 24.

  Further, when the mobile phone (communication terminal device) 23 is in the first mode, a mode indicator (mode display means) 26 is displayed on the screen display unit 25, and the mobile phone (communication terminal device) 23 is set to the second mode. In some cases, the mode indicator (mode display means) 26 is not displayed on the screen display unit 25.

  In the above embodiment, when the mode switching signal 16 is at a low potential, communication cannot be performed, and when the mode switching signal 16 is at a high potential, communication is not suspended. On the contrary, when the mode switching signal 16 is at a high potential, the communication cannot be performed, and when the mode switching signal 16 is at a low potential, the communication is not performed. It may be in the state of

  Further, when the mobile phone (communication terminal device) 23 is in the first mode, a mode indicator (mode display means) 26 is displayed on the screen display unit 25, and the mobile phone (communication terminal device) 23 is set to the second mode. In some cases, the mode indicator (mode display means) 26 is not displayed on the screen display unit 25. Conversely, when the mobile phone (communication terminal device) 23 is in the first mode, the mode indicator is displayed on the screen display unit 25. The mode indicator (mode display means) 26 may be displayed on the screen display unit 25 when the (mode display means) 26 is not displayed and the mobile phone (communication terminal device) 23 is in the second mode. .

  In the above embodiment, two variable gain amplifier circuits are provided, but the reception gain can be controlled in the same manner even if one or three or more are provided.

  Moreover, in the said embodiment, although the mode switching circuit 15 which outputs the mode switching signal 16 was provided, the mode switching signal was not provided but the mode switching signal was provided from the control part (not shown) with which the communication terminal device 1 was equipped. 16 may be output.

  In the above embodiment, the AGC signals 17 and 18 are generated by the D / A conversion circuits 21 and 22, but instead of the D / A conversion circuits 21 and 22, the number of pulses corresponding to the AGC signals 17 and 18 or The AGC signals 17 and 18 may be generated by a combination of a pulse generation circuit that generates a pulse having a pulse width and a low-pass filter.

  As described above, the mode switching circuit (mode) that switches between the first mode in which the communication of the wireless communication unit (wireless communication unit) 2 is stopped and the second mode in which the communication of the wireless communication unit (wireless communication unit) 2 is not stopped. Switching means) 15, and the upper limit of the receiving gain of the broadcast receiving unit (broadcast receiving means) 3 in the first mode is higher than the upper limit of the receiving gain of the broadcast receiving unit (broadcast receiving means) 3 in the second mode. If the mode is switched to the first mode when communication is not performed, the broadcast receiving unit (broadcast receiving unit) 3 is not saturated due to the interference caused by the transmission wave from the wireless communication unit (wireless communication unit) 2, and the broadcast receiving unit (Broadcast receiving means) The upper limit of the receiving gain of 3 can be increased.

  Furthermore, the upper limit of the reception gain of the broadcast receiving unit (broadcast receiving unit) 3 in the second mode is a value that does not saturate the broadcast receiving unit (broadcast receiving unit) 3 due to interference from the wireless communication unit (wireless communication unit) 2. Therefore, when communication is performed, the upper limit of the reception gain of the broadcast receiving unit (broadcast receiving unit) 3 is set by switching to the second mode so that the broadcast receiving unit (broadcast receiving unit) Means) 3 is lowered to a value that does not saturate, and even if a large interference wave is input from the wireless communication unit (wireless communication unit) 2, it is possible to avoid saturation of the broadcast receiving unit (broadcast receiving unit) 3. In addition, since the reception gain is set continuously low while the wireless communication unit (wireless communication unit) 2 is performing communication, the change in the reception power of the interference wave from the wireless communication unit (wireless communication unit) 2 is fast. However, there is no need to adjust the gain in time.

  Furthermore, since the mode switching in the mode switching circuit (mode switching means) 15 is performed based on an instruction from the user of the communication terminal device 1, the mode is switched at a timing preferred by the user of the communication terminal device 1.

  Further, since the mode switching in the mode switching circuit (mode switching means) 15 is automatically switched to the second mode by the communication start operation of the user of the communication terminal device 1, the user performs the communication. There is no need to perform a switching operation from the first mode to the second mode.

  Further, since the communication terminal device 1 has a mode indicator (mode display means) 26 for displaying that the communication terminal device 1 is in the first mode or that the communication terminal device 1 is in the second mode, the user can easily select the mode. Can be identified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, showing an embodiment of the present invention, is a block diagram showing a main configuration of a communication terminal device. It is a block diagram which shows the principal part structure of the automatic gain control circuit in embodiment shown in FIG. (A) thru | or (c) are timing diagrams which show the example of the maximum value adjustment of the AGC signal in embodiment shown in FIG. It is an external view which shows the mobile telephone which is an example of the communication terminal device of embodiment shown in FIG. 1 with the example of a screen display. It is a block diagram which shows a prior art and shows the principal part structure of a communication terminal device. It is a block diagram which shows the principal part structure of the automatic gain control circuit contained in the prior art shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication terminal device 2 Wireless communication part (wireless communication means)
3 Broadcast receiving part (broadcast receiving means)
4, 5, 27 Antenna 6, 9, 28, 31 Filter 7, 10, 29, 32 Variable gain amplifier circuit 8, 30 Frequency converter circuit 11, 33 A / D converter circuit 12, 34 Demodulator circuit 13, 35 Automatic gain control Circuits 14, 37 A / D conversion data 15 Mode switching circuit (mode switching means)
16 Mode switching signal 17, 18, 39, 40 AGC signal 19, 41 Averaging circuit 20, 42 Arithmetic circuit 21, 22, 43, 44 D / A conversion circuit 23 Mobile phone 24 Mode switch 25 Screen display unit 26 Mode indicator (Mode display means)
36 Saturation detection circuit 38 Saturation detection signal.

Claims (5)

Wireless communication means for communicating with a wireless base station;
In a communication terminal device comprising broadcast receiving means for receiving a broadcast from a broadcast base station,
Mode switching means for switching between a first mode for stopping communication of the wireless communication means and a second mode for not stopping communication of the wireless communication means;
The communication terminal apparatus, wherein an upper limit of a receiving gain of the broadcast receiving unit in the first mode is higher than an upper limit of a receiving gain of the broadcast receiving unit in the second mode.   The communication terminal apparatus according to claim 1, wherein the upper limit of the reception gain of the broadcast receiving means in the second mode is a value that does not saturate the broadcast receiving means due to interference from the wireless communication means. .   The communication terminal apparatus according to claim 1, wherein the mode switching in the mode switching means is performed based on an instruction of a user of the communication terminal apparatus.   The communication terminal apparatus according to claim 1, wherein the mode switching in the mode switching means is performed so as to automatically switch to the second mode by a communication start operation of a user of the communication terminal apparatus.   The communication terminal apparatus according to claim 1, further comprising mode display means for displaying that the communication terminal apparatus is in the first mode or that the communication terminal apparatus is in the second mode.

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